Carbon coated copper mesh grids

For routine TEM of cell and magnetosome morphologies, cultures were grown under microoxic conditions in FSM. Overnight cultures were fixed in 1.5% formaldehyde and deposited onto carbon-coated copper-mesh grids (Science Services, Munich, Germany). TEM was performed on a JEOL 1400 (Japan) with an acceleration voltage of 80 kV. Micrographs were analyzed using the software ImageJ [58 ].
For analysis of unidentified electron dense particles (uEDP), bright field TEM, high-resolution (HR) TEM and energy-dispersive X-ray spectroscopy (XEDS) were performed on a spherical aberration corrected JEOL ARM 2100 at an acceleration voltage of 200 kV and an emission current of 10 μA.

For transmission electron microscopy (TEM) analyses of M. gryphiswaldense cells and isolated magnetosomes, specimens were deposited onto carbon-coated copper-mesh grids (Science Services, Munich, Germany). Isolated particles were additionally negatively stained with 2% uranyl acetate. TEM was performed on a JEOL 1400 (JEOL, Tokyo, Japan) with an acceleration voltage of 80 kV. Images were taken with a Gatan Erlangshen ES500W CCD camera.
For localization studies, neurons, both control and stretched, were fixed with 1.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, at pH 7.4. After rinses with the same buffer, cells were post-fixed in reduced osmium tetroxide solution (1% OsO₄, 1% K₃Fe(CN)₆, and 0.1 M sodium cacodylate buffer), stained with our homemade staining solution [52 (link)], dehydrated in a growing series of ethanol, and flat-embedded in epoxy resin.
Ultra-thin sections (90 nm) were cut with a UC7 LEICA ultramicrotome (UC7—Leica Microsystems, Vienna, Austria) and collected on 300 mesh copper grids (EMS—Electron Microscope Science, Hatfield, PA, USA).
Images for morphological characterization have been collected with a Transmission electron microscope Zeiss LIBRA 120 Plus operating at 120 KeV equipped with an in-column omega filter.

For conventional transmission electron microscopy (TEM) of cell and magnetosome morphologies, cultures were grown under microoxic conditions in FSM at 28 °C. Overnight cultures were fixed in 1.5% formaldehyde and adsorbed onto carbon-coated copper-mesh grids (Science Services, Munich, Germany). TEM was performed on a JEOL 1400 (Japan) with an acceleration voltage of 80 kV and micrographs were analyzed using the software ImageJ [98 ].